The key selling point of the Amazon MPS is familiarity to mobile shoppers. Instead of chasing them off with yet another system they need to sign up for, MPS lets Amazon fans sign up to pay via phone. Shoppers can even enable Amazon’s 1-Click function. I worry about what I might accidentally buy from my pocket, but it’s good to have the option.

Amazon selected game and app seller Handmark as its first customer for reporters to pounce on. To be clear, Handmark is offering Amazon Payments to mobile customers as just one of several payment options. Customers can still pay through credit cards, PayPal and carrier billing.

Handmark VP of marketing Evan Conway told mocoNews that carrier billing is often presumed to be the most convenient method of payment, since the shopper doesn’t need to enter any info to make a purchase. Amazon’s 1-Click, though, has a brand allegiance and level of trust that American mobile carriers still haven’t built among their customers.

When AT&T calls me from two different 800 numbers during my workday trying to get me to pay my bill, I can’t help thinking that if they put an Amazon button on my iPhone’s screen instead, I could tap it and be done.